Process and apparatus for extracting zinc



Dec. 13, 1927.. 1,652,184

J. s osMARK PROCESS AND APPARATUS FOR EXTRACTING ZINC Filed April 9. 1925 ja mvEm'oR (7 BY v ATTORNEY Patented Dec. 13,1927.

JOHN sxoemaax, or new YORK,

This invention relates to a process of, and apparatus 7 for, extracting zinc from zinc bearing material, either in the form of powder.

The object of the invention is to provide such a process and apparatus which will be economical and .eflicient in operation.

In carrying out my invention I employ a shaft furnace of the blast furnace type. And I so direct the course of the blast and the gaseous products of combustion with reference to that are charged into the top of the furnace, and make such provision for the exit of the resulting zinc-bearing gases, high, yield of zinc and at the same time over-- come thedifliculties in attempting to extract zinc from ores in furnaces of this general type. I

The principal methods now in commercial use for extracting zinc are deposition, (2) electrothermic smelting and (3) retort distillation. electric power is available, the latter process is the one generally used. The disadvantages of this process are as distinguished from a continuous one, that it involves the use of small sized units, and that the labor costs are high. v

It has heretofore been proposed to overcome stream in sufficient quantity the zinc vapor and contaminate it with an excess of zinc oxide. zinc powder (which is the form in which most stream) is coated with oxide to such an extent that it cannot beproperly the furnaces that are now generally used for reducing metallic zinc powder to liquid metal. I

y described, I avoid this di a zinc powder of a character that can readily be reduced to liquid zinc.

The accompanying drawing, trates more or lessdiagrammati'cally, one

UNITED STATES P N. Y., ASSIGNOR OF ONE-HALF T0 MARCH F. CHASE.

PROCESS AND APPARATUS FOREXTR-ACTING ZINC.

Application filed. April 9, I925. Serial No. 21,803.

the zinc being recovered liquid spelter or zinc ous the zinc ore and other materials that I obtain a out heretofore experienced an (I) electrolytic Except where cheap that it is a batch process,

ing

by continuously the vapor in a into which these disadvantages because, when cold mainto a furnace of this carbon dioxide is formed in the gas to react upon The result is that the of the zinc is removed from the gas worked in ble my process and apparatus now to be culty, and produce which illusthe where heavy re resulting from the, operations, The usual tuyeres 3 mospheric gases, may

at 6. Valves 12 are provided fo the amount of gases by-passed in this way.

-At the top of the f apparatus. charged thro mixture of Z1110 bearing ore,

and a suitable amount 0 of forming a liq provided at the tuyeres ore is present principally oxide. The oxygen of th with the carbon of the charge to form 0 monoxide (G0) a short tuyeres, at a temperat 1500 C.

At point 4 a large are ing up part of the gases are reintroduce 6. At this point the gases ent heat to cause the reducreducive the t is that the charge deoint 6 contains a mixlead, slag formsome zinc oxide say 900 an charge column'at still contain suflici tion of substantially all of the easil point 6. The resul scending beyond the ture of carbon, metallic iron, ing material, some zinc and all' at a temperature of between, 1050. C.

This charge now en gases contain suflicient eat to embodiment of my invention, is a vertical section of a form of blas may employ. This furnace 1, has a hearth 2, duced metals and the slag may collect. are provided for applying the blast containing oxygen. Either atair, or. some other mixture ofbe used for this purpose. Th by-pass 5 (of which there may be a number) is adapted to by-pass part or all of the gase- -products of combustion, taking them off at 4 and returning th improved agentv in the form of ore and the t furnace which I em to the furnace shaft r regulating urnace the gases pass at 7 through the fume catcher 14: (where solid matter carried by thegas is collected) .and thence through the outlet 15, to be utilized in any desired way.

Provision is made at 9 for th zinc bearing gases removed in the condenser 10.

I shall now describe the manner in which rocess is carried out in this er starting the furnace it is ugh the charging door 8 with a a proper reduccarbonaceous fuel, f material capable uid slag with the gangue of ash of the fuel. A blast is 3. The zinc in the in the form of zinc e blast combines e exit of the from which the zinc is arbon distance above the ureof say 1400* part of these hot gases by-passed through 5, the remainder passv through the furnace. The ,bg -pa t0 oxides present in the charge a hot gases not bycounters the part of assed at 4. These complete the completely converted to charge.

withdrawn at point 9 may which casethere still reduction of the zinc oxide, and vaporize the zinc, producing zinc vapor. These gases passing up the shaft from 4 to 6, being reduced in volume and in constant contact with the incandescent carbon in the charge during a comparatively long period, are carbon monoxide. Thus, an atmos here favorable to the existence of metal ic Vapor is maintained at this zone, and the formation of detrimental g uantities of carbon dioxide is avoided.

he gases in this zone containa much larger percentage of zinc vapor than they would if the by-pass 5 were omitted.

At point 9 those gases, or a part of them, are withdrawn to the condenser 10, where the zinc is condensed out in the form of 1i uid zinc, or zinc powder. Ordinarily it will be condensed into the powder form which is conveyed away veyer 13. This powder may then be treated in a well know-n manner to obtain liquid zinc.

Between point 4 and point 9 at times it may be advantageous to introduce a small quantity of highly heated airor gas containing a higher percentage of. oxygen than ordinary air in order to supplv through the combustion of part of the carbon in this p0rtion to the charge sufficient heat to C011]? pletely volatilize the zinc that is in the For this purpose the tuyeres 11 are provided.

It is evident that the uantity of gas be less than the gas current ascending the shaft at-4, in will bean ascending current from 9 to 6. Under certain conditions, however, it may befound advantageous to withdraw a larg point 9 than is ascending the shaft at this point, in which case there will be a descending current from point 6 to point 9. These different operating conditions may be conveniently regulated by the. amount of gas liberated through 15.

The progress of the charge may be described as follows: (1) Above point 6, drying and duction 0 iron lead, etc. to point 4, reduction and (2) From point 6 vaporization of em loyed are .used :an not oflimitation,

by the screw con? claimed.

er amount of gas at,

preheating of the charge and re-.

ZnO and withdrawal of gas mixture at point 9 (3) From point 4 to point 3, zone of combustion of all the sla and it is economical in. operation.

The terms and expressions which I have as terms of description and I have no intention in the use of such terms and expressions, of excludin any e uivalent of the features shown and escribei l, or portions thereof, but recognize that various modifications are possible within the scope of the invention What I claim is: U

1. The process of extracting zinc from zinc bearing materials which consists in maintaining in a shaft furnace a suitable charge of zinc bearing material and carbonaceous'fuel, applying an air blast near the bottom of suc c arge, by-passingirom a lower zone to an upper zone a part of the gaseous products of combustion formed in the lower zone, thereby preheating the portion of the charge in the up r zone, and withdrawing from a zone in t e shaft itself intermediate the ends of the by-pass gases containing zinc vapor.

2. The process of extracting zinc from zinc bearing materials which consists in maintaining in a shaft furnace a suitable charge of zinc bearing material and carbona'ceous fuel, applying an air blast near the bottom of such charge, by-passing from a lower'zone to an upper zone a part of the gaseous products of combustion formed in the lower zone, withdrawing from a zone in the shaft itself intermediate the ends of the by-pass gases containing zinc vapor, and ap plying a blast to the lower part of the lntermediate zone.

JOHN SKOGMARK. 

